This invention relates to a twin control arm axle assembly for vehicle wheel suspension systems.
From German Patent Document DE-40 21 896 C1, a wheel suspension is known for steerable front wheels of motor vehicles in the case of which lateral-force understeering elastokinematics are achieved by way of a guiding joint on the wheel carrier which is constructed to be soft in the transverse direction of the vehicle and harder in its longitudinal direction.
It is an object of the invention to provide a twin control arm axle with a control arm bearing of a defined elasticity which excludes an elastokinematic control function of the wheels under the effect of forces and ensures a wheel suspension that insulates rolling noises as well as longitudinal shocks.
According to the invention, this object is achieved by means of a wheel suspension arrangement including:
a wheel carrier which supports a vehicle wheel, PA1 a lower control arm unit connecting the wheel carrier to a vehicle body in an articulated manner, PA1 and an upper control arm unit connecting the wheel carrier to the vehicle body in an articulated manner, PA1 wherein the upper control arm unit includes a control arm connected to the wheel carrier by way of an elastic control arm bearing which has defined bearing characteristics with respect to different in use driving forces acting on the wheel carrier with said control arm bearing being stiffer in transverse directions and in the vehicle longitudinal driving direction than in the direction opposite the vehicle longitudinal driving direction.
The advantages achieved by means of the invention are essentially that, because of the connection of the upper control arm to an elastic control arm bearing of the wheel carrier which is constructed to be harder in the transverse direction of the vehicle and in the driving direction than against the driving direction, a possibility is provided to buffer shocks exercised on the wheel in order to avoid noises. In addition, it is avoided that the wheel is influenced by the effect of braking forces and lateral forces on the wheel so that no disadvantageous control function can occur by way of the elastic control arm bearing.
The control arm bearing is preferably constructed as a vertical ball joint, in which case the spherical part of the joint is embedded in a surrounding rubber elastic layer and is surrounded by a bearing housing. The soft area of the control arm bearing is formed by a recess in contrast to the harder areas which are constructed as massive layers.
A limiting device for the control arm bearing is formed by a bent metal plate of a reinforcing plate in the rubber elastic layer. This bent plate reaches over the bearing to the control arm eye.
The soft area of the control arm bearing formed by the recess may have opposite rubber elastic layer parts which may impact on one another during the operation. Likewise, a center area of the layer parts may be arched to the front.
The control arm bearing of a defined elasticity can be used for a rear axle as well as for a front axle. In the case of a rear axle, the elastic control arm bearing may make a subframe unnecessary that is connected between the wheel suspension and the vehicle body because the longitudinal suspension is now absorbed by the bearing.
In particular, it is possible to advantageously use the elastic control arm bearing in the case of an upper control arm which is constructed as an A-arm and a lower control arm device which comprises two or three individual control arms.
Because of the construction of the elastic control arm bearing on the wheel carrier, almost no movement of the spherical part of the joint is possible in the transverse and braking direction, that is, in the driving direction, so that a windup during braking can also not take place.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.